DataReader尽管被特别关闭，但在while循环中的连接上打开

Question

  

已经有一个与此命令关联的开放DataReader   必须先关闭。

好。所以。我们在这里做了很多数据库读取，足以证明通用函数可以简化它。我刚刚更改了它，所以当用一个活动的函数调用时，函数不再关闭连接，因为它是一条线路。这样做，我发现了这个bug。在while循环的第二次迭代中，DBRead函数在尝试实际执行时会出错，并按照上述错误进行抱怨。 然而。在每次迭代结束时，都有一个没有条件的reader.Close（）调用。

现在......我已经做了一些环顾四周的事情，并发现了一些关于使用using这些的事情...说实话，我不确定我会怎么做（我可以很快就弄清楚，我猜，但是，我不知道它是否能解决这个问题。

我读到的其他问题实际上并没有结束。在这种情况下，我认为我在每次打开时，在读者上调用一个关闭，然后在之后重新使用连接。我有多难？

        // Find all the unprocessed gifts in the inhouse table.
        SQL = "SELECT * FROM ToREgift WHERE processed = 0";
        ReadCommand.Connection = ReadConnect;
        ReadCommand.CommandText = SQL;
        dbRERead = ReadCommand.ExecuteReader();
        while (dbRERead.Read())  // Loop through them.
        {
            RowId = Convert.ToInt32(dbRERead["id"].ToString());

            // Lookup the RE ConstituentId from the ToREConstituent table.
            string ToREConstituent_Id = dbRERead["ToREConstituent_id"].ToString();
            Reader = FunctionsClass.DBRead(vars.Catalog, "SELECT Constituent_Id FROM ToREConstituent WHERE ID = " + ToREConstituent_Id.ToString(), ref Connection);
            Reader.Read();
            string ConstituentId = Reader["Constituent_Id"].ToString();
            bool UseRG = false;
            try
            {
                UseRG = Convert.ToBoolean(dbRERead["Use_RG"]);
            }
            catch (Exception ex) { }
            ;

            if (!UseRG)
            {
                if (dbRERead["TypeOfGift"].ToString() == "RecGiftPC")
                {
                    UseRG = true;
                }
            }

            AddSingleGift(ConstituentId, UseRG, RowId);

            SQL = "SELECT Constituent_Id FROM ToREConstituent WHERE Id = " + ToREConstituent_Id;
            dbRECommand.CommandText = SQL;
            Reader = dbRECommand.ExecuteReader();
            while (Reader.Read())
            {
                ConstituentId = Reader["Constituent_Id"].ToString();
            }
            Reader.Close();

        }
        dbRERead.Close();

--

public static SqlDataReader DBRead(string DB, string SQL, ref SqlConnection Connection)
{
    SqlDataReader functionReturnValue = null;
    // !! IMPORTANT !!
    // This will initialise and open a connection as needed.
    // The caller is responsible for closing the connection
    if(Connection==null)
    {
        Connection = new SqlConnection();
    }
    if(Connection.ConnectionString=="")
    {
        Connection.ConnectionString = "Data Source = REDEV;Initial Catalog = " + DB + ";Integrated Security = True";
    }
    try
    {
        Connection.Open();
    }
    catch (Exception ex)
    {
        if(ex.Message!="The connection was not closed. The connection's current state is open.")
        {
            throw ex;
        }
        // Else continue, because if that's the error, doesn't matter, just move on.
    }
    SqlCommand dbCommand = new SqlCommand();

    dbCommand.Connection = Connection;
    dbCommand.CommandType = System.Data.CommandType.Text;
    dbCommand.CommandText = SQL;
    dbCommand.CommandTimeout = 0;

    try {
        functionReturnValue = dbCommand.ExecuteReader();
        return functionReturnValue;
    } catch (Exception ex) {
        //frmMain.BatchError = true;
        System.Windows.Forms.MessageBox.Show("Error reading Database. Can't Continue, sorry. Debug information below:" + vars.vbCrLf + vars.vbCrLf + ex.Message + vars.vbCrLf + SQL + vars.vbCrLf + vars.vbCrLf + Connection.ConnectionString);
        Connection.Close();
        System.Environment.Exit(0);
    }

    return functionReturnValue;
    // Cleanup
    //dbCommand = Nothing

}